Reconstructive surgeries employ soft tissue expansion techniques to create a stretched area of skin for prosthetic implant placement. A conventional tissue expander comprises an expandable balloon placed beneath a patient's skin or muscle that is gradually expanded to achieve a desired expanded tissue pocket. Soft tissue expansion may have advantages over conventional skin grafting for forming the tissue pocket, including providing a natural appearance in skin texture and color by matching the surrounding skin and an existing blood supply.
Tissue expanders may be used for surgical breast reconstruction following a mastectomy. Breast reconstruction involves a multistage process in which the affected breast tissue and skin is removed in a first surgery (mastectomy). A collapsed or partially inflated tissue expander may be placed under the pectoralis major muscle behind the area of the removed breast during the first surgery to create a new breast pocket. The tissue expander may be post-operatively filled with a filler material, such as saline or air, over several days, weeks, or even months until the breast pocket achieves a desired volume to accommodate a final permanent breast implant. In a subsequent surgery, the tissue expander may be removed and replaced with the final permanent breast implant, or the breast may be reconstructed with the patient's own tissue with tissue flap surgery.
Current breast tissue expanders comprise a silicone elastomer shell with an injection port for the filler material. Breast tissue expanders typically present a round full breast shape, a partial breast shape, or a contour shape for greater lower pole volume expansion of the breast pocket. Some breast tissue expanders may further include suture tabs for suturing the tissue expander to tissue on the patient's chest wall. The suture tabs, however, are often small and difficult for the surgeon to access during surgery.
Once implanted under the pectoralis major muscle during the first-stage surgery, a fibrous capsule of scar tissue forms over the tissue expander as part of a normal physiologic response to a foreign object. This encapsulated breast pocket ultimately receives the final breast implant. The thickness of the capsule may range from thin to heavily-thickened, and the fibrous capsule formation may offer inadequate space or an undesirable shape incapable of providing a desired teardrop-shaped breast pocket. The teardrop shape of the breast pocket provides a natural-looking breast with either a round or an anatomically-shaped final permanent breast implant. The fibrous capsule may also exhibit capsular contracture, constricting the breast pocket and causing deformation of the breast pocket, excessive firmness of the breast pocket, and/or pain.
As a result, in the subsequent surgery, surgeons routinely perform an open capsulotomy to further modify the breast pocket and achieve the desired size and shape for the final permanent breast implant. The capsulotomy results in additional surgical time, complexity, and cost. Since the capsulotomy necessarily results in additional trauma to the tissue surrounding the breast pocket, the patient may experience additional pain and a longer recovery time. Further, the patient may develop complications, such as tissue necrosis, bleeding, and/or irregularities in the chest wall and/or skin.